Evaluation of the behaviour of a thermal diffusion sensor in a high field strength magnetic resonance system: an experimental study.

Patients with acute brain pathology requiring ferromagnetic bio-medical implants for on-going invasive monitoring are largely excluded from the benefits of MRI scanning. We evaluated the behaviour of a thermal diffusion cortical blood flow (TD-CBF) sensor both in vitro (phantom gelatin model) and in vivo environments in a high field strength MRI system.Two baboons underwent cranial subdural implantation of 2 TD-CBF sensors/hemisphere and a single left parietal sensor was implanted subcortically to determine any deleterious effects. Using standard MRI sequences, artefact size, thermal effects, current generation, movement and reliability of recordings were assessed during scanning.The deflection forces were negligible, no observable thermal effects were demonstrated, while wide fluctuations in cerebral blood flow recordings were recorded. Mean image artefact size for implanted sensors was 6 times larger than in vitro. Patients with an implanted TD-CBF sensor may be safely imaged provided the device is disconnected. The MRI images obtained are of an acceptable quality.     

Immunosuppression in liver transplantation: beyond calcineurin inhibitors.

Although calcineurin inhibitors (CNIs) remain the mainstay of immunosuppression in liver transplantation (LTX), their long-term toxicity significantly contributes to morbidity and mortality. The elucidation of mechanisms of alloimmunity and leukocyte migration have provided novel targets for immunosuppression development. The toxicities of these agents differ from that of the CNI and act additively or synergistically. CNI avoidance protocols in LTX have not been achieved routinely; however, pilot trials have begun to delineate the limitations and promises of such approaches. CNI-sparing protocols appear to be much more promising in balancing the early need for minimizing rejection while tapering doses and minimizing long-term toxicity.     

Serum electrolytes in children admitted with diarrhoeal dehydration managed with simple salt sugar solution

Diarrheal diseases constitute a major cause of childhood morbidity and mortality in Zimbabwe. Since 1982, it has been the policy in Zimbabwe to use home-based Salt Sugar Solution (SSS) as standard Oral Rehydration Solution (ORS) therapy for both prevention and management of dehydration. The recommended formula is incomplete, lacking both potassium and bicarbonate. It may not, therefore, be as efficacious as complete ORS for the prevention or correction of hypokalemia and acidosis during diarrhea. For this reason, a study was carried out at Harare Central Hospital to assess the type and prevalence of electrolyte abnormalities in dehydrated children who had previously been managed with oral salt sugar solution for acute gastroenteritis. 121 such referred patients had their serum urea and electrolytes estimated on admission prior to further management in the Unit; .38 (27.5%) cases of hypokalemia, 12 (8.9%) of hypernatremia, 52 (5.5%) of hypoatremia and 65 (45.7%) of severe acidosis (bicarbonate level 10 mmol/1) were documented. It is concluded that simple salt sugar solution is ideal for the prevention of dehydration but in cases of established dehydration the WHO complete formula is more appropriate for combating hypokalemia and severe metabolic acidosis.     

Carcinoid tumors of the lung: a diagnostic challenge in bronchial washings

Bronchial washings are used routinely in the diagnosis of lung tumors. However, unlike other tumors, the diagnosis of bronchial carcinoids on bronchial washings is difficult. We reviewed 17 cases of histologically proven bronchial carcinoids from the files of the cytology laboratory over a period of 15 yr (1986–2001). The bronchial washings and histology sections of all the cases were reviewed separately by two independent observers and the results tabulated. Two cases had inadequate bronchial washings for evaluation and were excluded from the study. A growth was identified on bronchoscopy in 13 of 15 cases. Initial cytologic diagnoses were ?adenocarcinoma/?carcinoid and suspicious of carcinoid in one case each. However, on review, tumor was identified in 10 of 13 cases initially considered to be negative. The possible reasons for a false‐negative report on initial cytology include the paucity of tumor cell fragments in the bronchial washings (5 of 12 cases showing only one to two tumor fragments) and their bland appearance, often being mistaken for benign columnar cells. This study highlights the potential pitfalls in the diagnosis of bronchial carcinoids on bronchial washings and underlines the importance of a diligent search in cases with high clinical suspicion and positive bronchoscopic findings. Diagn. Cytopathol. 2004;30:62–66. © 2004 Wiley‐Liss, Inc.     

Cytopathology of uncommon malignant renal neoplasms in the pediatric age group

Malignant renal neoplasms are common solid tumors in pediatric oncology practice. These include the common Wilms' tumor/nephroblastoma and the uncommon neoplasms such as clear-cell sarcoma of the kidney (CCSK), rhabdoid tumor, renal-cell carcinoma, and others. The aim of this study was to describe in detail the cytopathological features of the histopathologically proven uncommon pediatric renal tumors. Aspirates from Wilms' tumor, which are mesenchyme predominant, show clusters of spindle cells associated with the matrix material. Evidence of rhabdomyoblastic differentiation may be present. CCSK, classic subtype, is characterized by round to oval cells arranged perivascularly and also in sheets and clusters intimately associated with a metachromatic matrix mucopolysaccharide material better appreciated in May-Grunwald-Giemsa (MGG)-stained smears. The cells also have more abundant cytoplasm and may show nuclear grooves. Spindle-cell pattern of CCSK is difficult to diagnose on aspiration cytology. Renal-cell carcinoma of childhood shows similar cytological features as its adult counterpart. Rhabdoid tumor of the kidney is characterized by a monomorphic population of cells with abundant cytoplasm, eccentric nuclei with prominent nucleoli. Intrarenal yolk sac tumor is a rare neoplasm and shows severely pleomorphic cells on aspiration.Awareness of these entities is important for the practicing cytopathologist. Further, non-Wilms' renal malignant neoplasms must be distinguished from the common Wilms' tumor so that appropriate chemotherapy protocols may be instituted in cases where the tumor is in an advanced stage of malignancy.     

Serum immunoglobulin levels in paediatric patients with pneumonia

OBJECTIVE: To determine levels of serum immunoglobulins IgG, IgM and IgA in patients admitted with pneumonia to Harare Central Hospital paediatric wards. DESIGN: A cross sectional pilot study. SETTING: Harare Central Hospital, Department of Immunology, University of Zimbabwe; Department of Paediatrics, University of Zimbabwe; Immunology Laboratory, University of Utrecht (The Netherlands). SUBJECTS: 71 paediatric patients. MAIN OUTCOME MEASURES: Immunoglobulin profiles for children with pneumonia. RESULTS: Of the 71 children tested, 43 had high IgG levels of between two and half and five times the upper end of the normal age-matched reference range. While the same 43 children with high IgG had similarly elevated levels of IgM, only 25 of them had elevated IgA levels. Of this group of 43 children with hypergammaglobulinaemia, all but one, had antibodies to human immunodeficiency virus (HIV), 50% of whom had detectable levels of p24 antigen in their sera. A small minority, 4% of the 71 patients, had very low levels of total immunogloblins. CONCLUSIONS: High levels of total immunoglobulins occur frequently in children with pneumonia and are associated with the presence of HIV 1/2 antibodies and also p24 antigen.